The [14 C-N-methyl]-erythromycin breath test dosimetry complies with the French regulations for radiation safety.

Abstract The [14 C-N-methyl]-erythromycin breath test (14 C-ERMBT) is one of the most valuable probes for liver cytochrome P450-3A4 activity in humans. In order to extend the use of this test in France, we herein provide safety data regarding either patient dosimetry or worker exposure to [14 C-N-methyl]-erythromycin. In order to determine the maximum radiation exposure for patient and nuclear medicine technician following one intravenous 14 C-ERMBT [111 kiloBequerel (kBq)], we have used the dosimetric data gathered in animal studies and extrapolated to humans using a weight-based method, approximate data provided by the French Society of Radioprotection and erythromycin pharmacokinetics in humans, considering always the worst conditions for the patient and worker exposure determination. The radioactivity administered to a patient after one 14 C-ERMBT was equal to 108.8 kBq (i.e. 98% of the total radioactivity in the 14 C-erythromycin vial) leading to a patient effective dose of 20 microsievert (μSv) and a maximum effective dose after 14 CO2 inhalation by the exposed worker of 16 μSv compared with a mean individual annual effective dose from natural and artificial radioactivity exposure of 3500 μSv in France. The 14 C-ERMBT is safe and complies with the European regulations regarding the administration of 14 C-labelled compounds in humans. It can therefore be used in clinical research in France without any particular safety requirement. [ABSTRACT FROM AUTHOR]